1. Field of the Invention
The invention relates to a presentation screen for the presentation of still or moving visual images such as pictures, text or data to a group or a number of people in typical and everyday business, training, education, promotion or exhibition environments. The screen is of the diffusion type, using diffusion means for displaying the images on the front viewing surface. The screen may collapse into a smaller configuration such as to significantly increase its portability as required for being readily moved from room to room or travelling from place to place. The field of the invention also relates to the various forms of art that may be employed in its various embodiments as, or as part of, a visual display device.
The field of this invention is that of flexible, rear projection screens and is not intended to include front (i.e. reflective) display screen applications, active display screens or rigid screens.
2. Description of Prior Art
Visual Display by means of cathode ray tube (CRT) devices is commonly used for computer monitors and televisions and can have relatively large screens (up to 40 inch, 1 meter) but these are bulky and very heavy and thus not truly portable.
Visual display by rear projection such as in TV units can provide a large screen area but such devices are not yet common and again the devices are large and bulky and thus not truly portable.
Visual display devices using a Liquid Crystal Display (LCD) are common particularly in laptop computers and are highly portable but their limited screen size (14 inch, 35 cm) makes them unsuitable for presentational use involving several persons viewing the screen simultaneously in comfort.
Various other displays are appearing such as plasma screens that are large screen (up to 42 inch currently, 105 cm) and that are almost flat for hanging on a wall, but again are relatively heavy and bulky so not truly portable.
Visual display by large screen front projection means is popular in business and at home. Use may be in circumstances of a fixed set-up in a special room or for use in a portable or travelling manner. However the latter requires some preparationxe2x80x94possibly in front of a waiting client or audience. Depending on circumstances it may require suitable lighting conditions, a screen and the physical space to the projector screen to be available. This can be a further disadvantage when associated with use where visiting in a business environment since it may be considered professionally xe2x80x9cintrusivexe2x80x9d, to impose these requirements on a client even for informal presentations.
Many visual display devices have tried to employ the advantages of the systems above within a more or less portable package. In general these are subject to the limitations either that the viewable screen is smaller than the case within which it is carried, or where the display screen is larger than the case and in some way disassembled for storage and carriage, use of the screen requires user intervention to then assemble the screen and attach it to other required elements which is again an inconvenience and takes time.
There are known methods for the collapsing of seamless front projection screens that employ flexible screens which fold away for storage. However these collapsing methods have not generally proved applicable in translucent diffusion applications for the reasons set out below.
Front Projection screens are not translucent and therefore typically consist of a reflective front surface with a reinforced backing that provides considerable physical xe2x80x9cbodyxe2x80x9d to the material such that it does not require to be stretched to operate or reflect light uniformlyxe2x80x94although it may be hung or stretched to stay in an approximately planar condition. Further, physical damage such as creases or folds in the screen surface are not highly critical to the optical performance as no light passes through the-material.
Flexible screens suitable for use in say a portable rear projection application, are by necessity of their unique optical transmissive and controlled diffusive requirements, very thin, of a totally different translucent and very homogeneous material without any reinforcing layer, must be under at least minimal tension and physical distortion and non-planarity must be avoided. Further, any crease or fold of the material (even if not still physically present or not) may cause optical distortion to the passing light and images or cause xe2x80x9crainbow effectxe2x80x9d or xe2x80x9cwhite spotsxe2x80x9d and result in very irritating screen flaws to a viewer.
As a result, the technology of the screen, its material and also the optical and physical requirements in use are very different from those applicable to reflection screens. Further the demands of preserving the screen optical qualities and screen longevity (especially in required highly repeated or rapid opening and closing actions) are much more critical in xe2x80x9cfit for purposexe2x80x9d concerns. In consequence particular difficulties are encountered in developing collapsible screens of this type, and it has not been generally possible to apply collapsible concepts from the reflection screen art to screens designed for the application of the present invention.
Specifically, relevant prior art is list here:
D1: U.S. Pat. No. 4,323,301 (Spector D.) Apr. 6, 1982 A collapsible and portable flexible screen erected by inflating by gas cartridge a tubular rectangular loop.
D2: EP-A-0 424 074 (Failla S.) Apr. 24, 1991 Segmented rigid display screens that are collapsible by hinging/sliding means.
D3: EP-A-0676 893 (Projectavision Inc) Oct. 11, 1995 Cabinet for portable rear-screen television projector that features a light shield.
D4: U.S. Pat. No. 2,827,955 (Hurley A.) Mar. 25, 1958 Folding Motion Picture Screen (front projection only).
Accordingly:
It is an object of the present invention that it generates the viewable optical images on the front viewing surface of the presentation screen by the diffusion of the light comprising of images that originate from a light source at a distance to the rear of the front viewing surface.
It is an object of the present invention that it provides a visual display screen with a viewable surface area that is sufficiently large such that it may be readily and comfortably viewed by several people.
It is an object of the present invention that it may be viewed in typical in-door environments without need for further space or apparatus (other than if an external media source is required).
It is an object of the present invention that the screen assembly is collapsible such that the viewable screen area is considerably larger when in an open condition than its largest area of encumbrance when in a closed condition thus providing a portable nature suitable for carrying from room to room or for travelling from place to place.
It is an object of the present invention that it provides a visual display screen that presents a joint-less and essentially planar screen to a viewer situated in front of the viewing surface.
It is a desirable object of the present invention that it may be considered as xe2x80x9cself-collapsingxe2x80x9d that is to say that it can be deployed or collapsed as an integral assembly whereby the screen assembly does not require user intervention such that any parts be removed, added, attached, detached, re-located, tightened or loosened and requiring only a simple and direct opening or closing action.
It is an object of the present invention that it employs specific means or methods such as jointing means, mechanisms, elements, materials, shapes or geometrical configurations that are intended by their presence or operation or action to prevent or reduce any damage or deterioration of a physical or optical nature that may occur to the viewable screen area due to any single or occasional or often repeated action or movements or sustained positions of the collapsible screen assembly.
It is a desirable object of the present invention as, or as part of, a portable visual display device, to be readily and rapidly deployable to a useable state within a set-up time of several seconds.
It is a desirable object of the present invention as, or as part of, a portable visual display device, that it comprises true portability in a hand portable case.
Briefly stated, the objects of the present invention relate to a portable screen for presentation purposes that can be used as, or as part of, a visual display device that is practically and commercially suitable in its various embodiments for making presentations of a business, professional, promotional, marketing, advertising, communication, training or educational nature to many people situated in normally lit indoor environments such as in typical business environments, meeting rooms or offices, classrooms, lecture-rooms, exhibition halls, point-of-sale areas, gymnasiums etc., A possible embodiment of the invention is as an optional accessory to conventional projectors.
In accordance with the principles of the present invention, the foregoing and other objects are achieved by a screen assembly composed a surrounding rectangular frame member to which is permanently attached a viewable screen member composed of a material that is attached and supported within the said frame member. The screen member acts as a display screen by the diffusion of images on a front viewing surface, the images being produced by light-imaging elements or devices located to the rear of the forward facing viewing surface. The screen assembly includes jointing means permitting it to move as an assembly between two conditions such that it can be rapidly opened and used as a display device or rapidly collapsed into a closed condition that represents a much smaller configuration suitable for ready transport or storage.
Accordingly, a screen assembly for a portable visual display device comprises a frame member to which is permanently attached a screen member for the presentation of visual images on a front viewing surface to persons located on a viewing side by diffusion of optical images created to the rear of this front viewing surface (which is to say images that may originate from a distance from the rear of the screen, but which excludes reflecting screen front projection) wherein the screen assembly comprises at least two screen and frame sections connected by jointing means such that the screen assembly is deployable into a closed condition in such a manner as to significantly reduce the screen member area when in the closed condition.
Thus the screen assembly is collapsible such that the viewable screen area is considerably larger when in an open condition than its largest area of encumbrance when in the closed condition. The resulting assembly is potentially provided with a portable nature suitable for applications involving carrying from room to room or travelling from place to place.
It may be desirable for the screen to have a joint-less configuration on its viewable surface and to this end the assembly uses a screen member of a flexible nature, with the screen member comprising a flexible material.
The material of the screen member may be of a passive translucent nature suitable for the diffusion of optical images projected through the screen from a projection device located to the rear of the screen member.
The screen assembly may be composed of a screen member retained within a screen frame member having jointing means thereon (such as hinges or the like) such that any section of the screen assembly may fold about one or more axes determined by the jointing means in such a manner as to significantly reduce the screen member area when in the closed position.
The screen assembly and jointing means are preferably so configured that a screen and frame section (as determined by the frame jointing means such as hinges) may rotate or fold about the jointing means such that a screen section through approximately 180 degrees into a flat position adjacent to other screen and frame sections.
The screen assembly and jointing means are preferably so configured that the screen and frame sections may rotate or fold about the jointing means such that a screen section lies substantially perpendicular to another or several other screen and frame sections.
For example, the screen and frame sections may rotate by jointing means about the frame axis enabling outer screen sections to rotate so that the said outer sections are perpendicular to the remaining screen sections when in the closed condition.
The screen and frame sections of the screen assembly may be so arranged that sections of the screen assembly are enabled to rotate about at least two axes one of which is not parallel to any other axis, or at least two axes of which at least two are essentially parallel, or about two parallel axes and a third perpendicular axis.
The screen frame member may be provided with screen frame supporting panels or members that are attached by a jointing means to the edges of the screen frame such as to provide mechanical support to the screen assembly when in the open condition and to lie flat with the screen member when in the closed condition. A plurality of screen frame supporting panel members may be provided connected by jointing or hinging means. Some or all of the axes of rotation of the jointing means between frame supporting panels are preferably configured to fail essentially parallel and co-incidental or adjacent to axes of the jointing means of the screen assembly when the frame support members are closed flat against the screen member.
The frame supporting member or panel or multiplicity thereof is or are attached by a jointing means to the frame member and which lies flat and adjacent with the screen member when the screen assembly is in the collapsed position and deploys in such a manner as to provide substantial mechanical support to retain the screen assembly in the upstanding position and/or to retain the frame elements in the fully open condition for viewing of the screen images.
It is a preferable feature of the aforesaid screen assembly and jointing means that they are together configured to avoid or reduce any optical or physical damage or deterioration to the viewable surface of the material of the screen member that may be caused by any position thereof or due to any repeated opening or closing actions.
The jointing means may be configured such that they provide axes of rotation that are virtual or pseudovirtual or are axes that move out of the physical section of the frame elements or jointing means.
Another possible member is a base member that can be placed on a flat surface and to which the screen assembly and/or any present frame supporting member can be attached such as to be supported in the upstanding position upon or by the base member. This base member may be configured as an enclosure preferably with a lid into which the said screen assembly can be stored and secured for transport. The base member if constructed as an enclosure may also contain a media source to store the images.
Thus, the invention further comprises a portable visual display device comprising a screen assembly in accordance with any preceding claim wherein the screen assembly is mounted to a base member suitable for seating on a flat surface such that the base member provides support to retain the screen assembly in an upstanding position when in the open condition.
Within the context of its use as, or as part of, a visual display device then another possible member is a light-imaging means or device capable of creating the display images so.
Another possible member is a projection device whereby the images on the front viewing surface of the screen are generated by rear projection of the images through a translucent screen material suitable for such purposes. The projection device may be utilised as an integral, removable or attachable unit and may have associated with it a mirror or mirrors such that the optical light path from the projector can be folded back to thus reduce the physical pat h distance from projector to screen member.
The apparatus may optionally be provided with a light-shield member that may be used with the aforesaid projection device to ensure that ambient light cannot impinge on the rear side of the screen member to the detriment of image quality while the screen assembly is operational. This light shield is preferably also collapsible into a much smaller closed condition either with or separately from the screen assembly.
In a preferred arrangement the light shield is deployable in the open condition so as to be adjacent or attached to the upper horizontal and the upstanding frame elements of the screen assembly and to extend downwards and rearwards towards the base member.
The base member may be configured as an enclosure with a lid such that the enclosure lid when open acts as a part of the light shield.
The light shielding member may be jointed to the screen assembly such that it is collapsible from the open and deployed condition to a collapsed condition adjacent to the screen assembly, and preferably the light shielding member or any part or element thereof is jointed to a screen frame edge and acts as a frame supporting panel such as provide mechanical support to the screen assembly when in the open position. Also the light shielding member or any part or element thereof may act as a fold guide element that can be brought into a position adjacent and parallel to the axis of rotation of the screen assembly sections such as to act as a support or guide to the screen member material as it wraps around the fold guide elements during the rotation of the screen assembly sections during the closing actions and when in the closed condition.
A particular embodiment of the invention utilising a projection device can form a configuration that enables the screen and light shield member to be attached together by jointing means enabling them to open and close integrally as a single entity and to preferably collapse into the aforesaid enclosure. The light shielding member may be configured to collapse in a secondary collapsing movement in co-operation with the collapsing movement of the screen assembly such that the combined device collapses to a closed condition, and in such an arrangement the axes of collapsing of the light shielding member are preferably parallel and adjacent or co-incidental.
It is desirable that each or all of the aforesaid members or elements may be considered as xe2x80x9cself-collapsingxe2x80x9d, that is to say can be deployed without need for user intervention to deploy or collapse the assembly or combined assemblies other than by a direct action only to open or close (or short series of simple actions in the case of combined assemblies) or by actuation of a mechanical or motorised drive to perform the same.
Other alternative features of the invention will be apparent from the appended claims.